On 12/24/2018 5:51 AM, Bruno Marchal wrote:
On 24 Dec 2018, at 07:44, Brent Meeker <[email protected]
<mailto:[email protected]>> wrote:
On 12/23/2018 8:45 PM, Jason Resch wrote:
On Sat, Dec 22, 2018 at 9:33 PM Brent Meeker <[email protected]
<mailto:[email protected]>> wrote:
On 12/22/2018 12:04 PM, Philip Thrift wrote:
https://www.eurekalert.org/pub_releases/2018-12/lsu-be122018.php
Theoretical physicists developed a theory called loop quantum
gravity in the 1990s that marries the laws of microscopic
physics, or quantum mechanics, with gravity, which explains the
dynamics of space and time. Ashtekar, Olmedos and Singh's new
equations describe black holes in loop quantum gravity and
showed that black hole singularity does not exist.
"In Einstein's theory, space-time is a fabric that can be
divided as small as we want. This is essentially the cause of
the singularity where the gravitational field becomes infinite.
In loop quantum gravity, the fabric of space-time has a
*tile-like structure*, which cannot be divided beyond the
smallest tile. My colleagues and I have shown that this is the
case inside black holes and therefore there is no singularity,"
Singh said.
"These tile-like units of geometry--called 'quantum
excitations'-- which resolve the singularity problem are orders
of magnitude smaller than we can detect with today's
technology, but we have precise mathematical equations that
predict their behavior," said Ashtekar, who is one of the
founding fathers of loop quantum gravity.
But is this consistent with https://arxiv.org/abs/1109.5191v2
which showed spacetime to be smooth down to 1/525 of the Planck
length?
Brent,
Wouldn't this be a successful prediction of Bruno's theory? In
another thread you said it had only made retrodictions, but wasn't
one of Bruno's predictions that space and time would be continuous
(not discrete), therefore it would predict LQG is false, and then
https://arxiv.org/abs/1109.5191v2 would be a confirmation of that.
First, I don't see that his theory even predicts a topoloical space.
By the semantics available for S4Grz1, and the X1* logics.
How does that define open sets?
But intuitively, you can see them arising from the fact that the first
person indeterminacy has a continuum range, as the DU multiplies all
histories on all oracles (real numbers) in the limit of all
computations, which cannot be avoided from the first person views
associated to the machine.
But you haven't even defined a first persons' "views", appearance from a
given place. You need metric space and physiscs for that.
Second, Newton said space is a continuum so it's not a prediction
peculiar to Bruno.
Like the very existence of a physical observable universe, this is
explained by Mechanism. Aristotle took this for granted, and Newton
assumed the continuum at the start, which is not an explanation, even
if that was a very clever move to get the correct local prediction.
Note that Newton was aware that his theory was on shaky metaphysical
base, though.
Now, Mechanism predicts only that some observable are continuous. To
derive that time or position are such observable would need to get a
notion of space, which in the mechanist approach is the most difficult
things to get. We will get first the mathematics of knots, and derive
space from there, perhaps.
Which I take as an admission that you have not done so.
Brent
String theory suggest that space could be a continuum, unlike Quantum
Loop Gravity, and mathematically, string theory seems to be favoured
by Mechanism, but that remains quite beyond … the mathematical logical
tools available today ...
Bruno
Brent
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